Abstract
The effects of P, TP, and CA on hypothalamic PIF content, pituitary prolactin concentration, and mammary development were studied in mature ovariectomized rats. Each of the 3 steroids significantly decreased hypothalamic PIF content, increased pituitary prolactin concentration and, induced mammary growth. The TP and CA also elicited mammary secretion. These observations indicate that the stimulatory effect of the 3 hormones on pituitary prolactin secretion is mediated through the hypothalamus.